1. Field of the Invention
The invention relates to a sheet stapling device comprising at least one stapling head which for adaptation to different sheet formats can be moved in one direction along a travel path so as to be adjusted to various selectable stapling positions, and a plurality of anvils, which cooperate with the stapling head, are arranged in a row extending along the travel path in the adjusting direction, and each of which features or has first and second cooperating surfaces for cooperating with each of the two legs of a staple being ejected from the stapling head during a stapling operation, the cooperating surfaces being successively arranged in the longitudinal direction of the row of anvils.
2. Description Relative to the Prior Art
Stapling devices of this type are known. They are widely used in sheet handling equipment arranged downstream of the sheet exiting stations of copiers, printing machines, etc. Sheet handling equipment used in connection with copiers provided with means for collecting the copy sheets and collating them in sheet stacks in addition to stapling devices are also called finishers. In cases in which the sheets are stapled by means of a stapling device and subsequently folded along the central line to form a brochure or leaflet, the respective sheet handling device is also called a saddle stitcher.
Regardless of the specific design of such stapling devices, usually a first stapling head is fixedly arranged at a predetermined distance from the neighboring top (or bottom) edge of a sheet stack, while a second stapling head is arranged movably with respect to the first head such that it can be positioned equidistantly from the opposite bottom (or top) edge of the stack. The movable stapling head can be locked in these selectable stapling positions by means of releasable detents. The stapling positions are selected so as to correspond to the format steps of the sheet format systems in question, e.g , to the steps A4, A3, etc. with the DIN system or to the steps of the US systems (inch system). The anvils are arranged in a row such that opposite to said first stapling head an anvil with its two first and second surfaces is located, and such that opposite to the second head also an appropriately registered anvil with its two first and second surfaces is located in each of the adjustable stapling positions.